Brief Communication: Carcinoembryonic Antigen and Alpha-Fetoprotein in the Diagnosis of Gastric and Colonic Cancer: A Comparative Clinical Evaluation

Serum carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP) levels were simultaneously measured in 100 colorectal cancer patients and 45 gastric cancer patients. With local or regional malignant disease, CEA was abnormal (>2.5 ngjml) in only 11 of 27 patients with large-bowel carcinoma (41%) and in only 1 of 8 patients with carcinoma of the stomach (12%). AFP was not increased (>40 ngjml) in any of these patients. With distant metastasis, however, abnormal CEA levels were found in 60 of 73 colorectal cancer patients (82%) and abnormal AFP in 3 of 73 (4%). Two patients had concurrent elevations in CEA and AFP, and only 1 patient had an abnormal AFP in the presence of a normal CEA. The combined assays therefore did not significantly improve diagnostic sensitivity. On the other hand, among 37 gastric cancer patients with distant metastasis, 9 (24%) had abnormal CEA and 12 (32%) had abnormal AFP. Only 1 of the 12 patients with an elevated AFP also had elevated CEA. The combined assays, therefore, raised diagnostic sensitivity to 20 of 37, or 54%. In both colorectal and gastric carcinoma patients, elevation of AFP seemed independent of the presence or absence of liver metastasis. The combined determination .of serum CEA and AFP can significantly increase the detection rate of metastatic gastric carcinoma.